This invention generally relates to a data recording method and a data recording apparatus preferably being applicable to a case where it records data on an optical disc medium such as Digital Versatile Disc plus Rewritable (hereinafter called DVD+RW). More specifically, this invention relates to a data recording method and the like, wherein it records the data on the optical disc on a block unit basis using write clock generated on the basis of information given by the optical disc, with performing replacement procedures on a predetermined block area of the optical disc on which a predetermined block of data is to be recorded when the write clock corresponding to the predetermined block area fails to be correctly generated, and recording predetermined data using a reference clock that is different from the write clock, thereby preventing the predetermined block area from generating blank portion therein when performing the replacement procedures on the predetermined block area, and preventing disadvantage such as a tracking servo failure occurred in the predetermined block area when DVD-ROM drive or the like reproduces the optical disc.
In the DVD+RW disc, it has proposed that the data be recorded on a block unit basis. Here, one block unit indicates a recording block including an Error Correction Code (ECC). DVD+RW disc allows the data of one block unit to be recorded on its own one block area (including 16 sectors).
According to a format of the optical disc, defect management system is employed in general whereby if there is any defective block area, it performs the replacement procedures on the defective block area so that the optical disc is available for use without any problems.
When it, in particular, is formatted before using, a perfect certification allows any defective block area to be found. The defective block areas thus found are usually listed in the Primary Defect List (hereinafter called PDL) and it performs slip replacement as the replacement procedure on the defect areas as shown in FIG. 12. According to the slip replacement, the data to be recorded on the defective block area, if any, is recorded on a next block area that physically follows the defective block area. In FIG. 12, a reference number such as Nxe2x88x921, N, and N+1 indicates a number of the block.
The defective block areas found while using are listed in the Secondary Defect List (hereinafter called SDL) and it performs linear replacement as the replacement procedure on the defect area as shown in FIG. 13. According to the linear replacement, a replacement area to be replaced with the defective block area is selected in advance and if it finds any defective block area, the data to be recorded on the defective block areas is recorded on a block area in the replacement area. In FIG. 13, a reference number such as Nxe2x88x921, N, and N+1 indicates a number of the block.
Regarding DVD+RW with 3.0 GB capacity, the PDL and SDL are respectively recorded on Defect Management Area (hereinafter called DMA) set in the inner circle""s Lead-in area or in the outer circle""s Lead-out area, as shown in FIG. 14.
Regarding DVD+RW with 4.7 GB capacity, the defect management is simplified so that the defective block areas found while certification and using are recorded on Replacement List (hereinafter called RPL) as shown in FIG. 15. The RPL is equivalent to the above SDL. Therefore, according to the DVD+RW with 4.7 GB capacity, it performs only the linear replacement without performing the slip replacement. This produces merits of fixing an address of each of the block areas in spite of their replacement condition.
DVD+RW disc with 3.0 GB capacity has a format that is fairly different from a DVD-ROM format in a location of block area, presence of link sectors, presence of spear sectors in the data area and so on. The DVD-ROM drive, however, may reproduce the data from it by a simple change of its hardware and with its firmware referring to the PDL and/or SDL.
DVD+RW disc with 4.7 GB capacity gives top priority to compatibility with the DVD-ROM disc so that if the defective block area is not replaced by the replacement procedure, we can consider it to be compatible with the DVD-ROM disc. Even if the replacement occurs, the compatibility may be accomplished with a support of the firmware like DVD-ROM drive refers to the RPL.
In order for the DVD-ROM drive to reproduce the DVD+RW disc as the ROM, it retrieves a tracking error signal using Differential Phase Detection (hereinafter called DPD) method. According to the DPD method, the tracking error signal is detected on the basis of pits so that a blank portion may cause the tracking servo failure, and thus, this fails to access the subsequent block areas again. This also causes a lot of retries according to a firmware configuration. On the other hand, the DVD+RW drive records it on blank block areas and retrieves the tracking error signal from pre-groove using Differential Push Pull (hereinafter called DPP) method.
The DVD-ROM drive also retrieves address information from an ID stored on a top of each of the sectors in reproduction data. It is necessary, in order to retrieve the ID from a first sector of each of the block areas, that a reproduction RF signal is retrieved from a block area just before the same to lock Phase-Locked Loop (hereinafter called PLL) by which reproduction clock (read clock) is obtained and the IDs are correctly retrieved during a previously predetermined section for checking uninterruption of the addresses. Although, regarding DVD+RW drive, methods of retrieving the address information are fairly different from each other according to the DVD+RW disc with 3.0 GB capacity or 4.7 GB capacity, it may retrieve the information from Address in Pre-groove (hereinafter called ADIP) included in a wobble of the pre-groove according to either of the discs.
Therefore, regarding the DVD+RW disc, the followings are required for it to be compatible with the DVD-ROM in a physical level: no blank portion remains (of course, with the exception of the portion that is not necessary at all for being accessible thereto); and IDs can be retrieved during a previously predetermined section from a block area just before a block area recording the necessary data.
Accordingly, an object of the invention is to provide a data recording method and so on for preventing the predetermined block area of the optical disc from generating blank portion therein when performing the replacement procedures on the predetermined block area and preventing the disadvantage such as a tracking servo failure occurred in the predetermined block area when reproducing the optical disc.
According to the invention, we provide a data recording method for recording data on an optical disc on a block unit basis using write clock generated on the basis of information given by the optical disc, comprising performing replacement procedures on a first block area of the optical disc on which a predetermined block of data is to be recorded, when the write clock corresponding to the first block area fails to be correctly generated, and recording predetermined data on the first block area using a reference clock that is different from the write clock.
We also provide a data recording apparatus comprising write clock generating means for generating write clock on the basis of information given by an optical disc, data recording means for recording data on a block unit basis using the write clock generated by the write clock generating means, reference clock generating means for generating reference clock that is different from the write clock, and processing means for performing replacement procedures on a first block area of the optical disc on which a predetermined data block is to be recorded, when the write clock generating means fails to generate the write clock corresponding to the first data block area correctly, and allowing the data recording means to record predetermined data on the first block area using the reference clock generated by the reference clock generating means.
Further, we provide a data recording apparatus comprising write clock generating means for generating write clock on the basis of information given by reflected light from an optical disc, data recording means for recording data using the write clock generated by the write clock generating means, reference clock generating means for generating reference clock that is different from the write clock, and processing means for allowing the data recording means to record predetermined data on the first block area using the reference clock generated by the reference clock generating means when the write clock generating means fails to generate the write clock correctly corresponding to the first block area of the optical disc on the basis of the information given by the reflected light from the optical disc, during certifying process.
According to these inventions, the write clock is generated on the basis of the information given by the optical disc on the recording. It is illustratively generated either according to the PLL on the basis of the reproduction signal of Alternating Fine Clock Mark (hereinafter called AFCM) if the optical disc is DVD+RW disc with 3.0 GB capacity, or according to the PLL on the basis of the wobble signal if the optical disc is DVD+RW disc with 4.7 GB capacity.
On the recording, the optical disc usually allows the data to be recorded thereon on a block unit basis using the write clock thus generated. For example, the block indicates one ECC block constituting 16 sectors.
During such the recording, the replacement procedures are performed on the first block area of the optical disc on which a predetermined data block is to be recorded, when the write clock corresponding to the first data block area fails to be correctly generated. For example, when disturbing a reproduction signal of AFCM or a wobble signal, the PLL is unlocked so that no write clock can occur correctly.
As described above, the data recording is carried out on the first block area using the reference clock, a fixed clock that is different from the write clock when performing the replacement procedures on the first block area.
This prevents the predetermined block area from generating blank portion therein when performing the replacement procedures on the first data block area and prevents tracking servo failure occurred in the first data block area when a drive gets a tracking error signal on the basis of recorded pits (marks).
When it records the data using the above write clock on a second block area following the first block area that has recorded the data using such the reference clock, a clock component of the reproduction RF signal is interrupted across the boundary between the first and the second block areas so that the PLL may be unlocked and no reproducing clock (read clock) occurs correctly at the top of the second block area with a fear of failing to reproduce the data from the second block area. In order to avoid this, it will be enough if the replacement procedures are also performed on the second block area.
Further, even if the replacement procedures are performed on the second block area, the clock component of the reproduction RF signal is uninterrupted across the boundary between the second block area and a third block area following the second block area when normal write, which uses the write clock generated on the basis of the information given by the optical disc, is performed on the second block area, thereby correctly generating the reproducing clock on the third block area from which the data can be correctly retrieved.
When it records the data on the first block area using the reference clock as described above, there can remain a blank portion in a rear side of the first block area if a predetermined amount of the data to be recorded on the first block area is recorded on the first block area because the reference clock fails to be adapted for nonuniform rotation of the optical disc, etc. If there remains a blank portion in the first block area, this causes the tracking servo failure in the first block area. For this reason, when recording the data on the first block area using the reference clock, it will be better to record the data on the second block area across the first block area. This is implemented by increasing an amount of the data to be recorded or reducing a frequency of the reference clock.